Aristotle believed in four elements, air, water, fire and earth. he believed that no matter how many times you cut something in half, you still get a smaller peice of that matter.
Arostotle's Atomic Model
Around 400 B.C.E, a scientist named Democritus believed that if you keep cutting something in half it becomes an atom. He proposed that these tiny particales called atoms, make up all matter everywhere.
In 1803 scientist John Dalton reintroduces the concept of atoms that Democritus made with with actual evidence to support his claims and ideas.
Dalton's Atomic Model
In a 1897, J.J Thomson he identified particles that are present in every single atom.
Thomson's Atomic Model
Millikan's Atomic Model
In 1909 Robert Millikan determined the unit charge of the electron.
In 1911 Ernest Rutherford discovered the positivley charged nucleus of an atom.
Rutherford's Atomic Model
Neils Bohr discovered in 1913 that electrons move about the nucleus in paths.